Assessing and Reducing Taxi Drivers' Exposure to Ultrafine Particles

描述（由申请人提供）：在城市环境中，车辆排放物通常是超细颗粒（UFP，直径<0.1微米）的最大来源，毒理学研究的有力证据表明，UFP每单位质量的毒性大于规定的较大颗粒。预计出租车司机将接触到高水平的UFP，因为他们靠近源头，接触时间较长。然而，关于出租车司机在工作中暴露于非机动车颗粒物的数据和知识存在重大差距，关于导致高暴露的影响因素的知识更是少之又少。缺乏此类知识是一个重要问题，因为在获得有关接触原因和相关性的可靠数据和知识之前，无法完成定量UFP接触/风险评估，也无法制定适当的UFP缓解政策。我们的长远目标是减少因在工作场所接触不合格食品而导致的职业病。本建议的目的是开发UFP暴露评估工具，并为出租车司机探索新的低成本UFP暴露缓解策略。核心假设是：1）车辆特性和驾驶条件将解释出租车司机暴露于UFP的总变异性的很大一部分; 2）用高效微粒空气（HEPA）过滤器替换商业安装的车厢过滤器将显著减少出租车司机暴露于UFP。在初步数据的指导下，这一假设将通过追求两个具体目标进行检验：1）通过确定影响出租车车厢内UFP浓度的主要因素，开发暴露评估工具; 2）开发新的低成本暴露缓解策略，以减少出租车司机对UFP的暴露。这将是第一项评估美国出租车司机UFP暴露的系统性研究，也是第一项探索降低出租车内UFP水平的成本效益技术的研究。这项研究将惠及的士司机（他们通常每周工作72小时）和易受影响的乘客（例如较频密需要的士服务的长者和残疾人士）。我们将同时监测40辆出租车内外的UFP和其他车辆排放污染物水平，建立统计模型来预测车内UFP水平，并测试用HE-PA过滤器改装商业安装的车内空气过滤器将在多大程度上降低车内UFP水平。拟议研究的理由是，开发的暴露模型将促进后续的健康影响研究，确定的缓解策略将产生新的创新方法，以防止出租车司机在工作中接触高UFP。拟议的研究是创新的，因为它代表了一个新的和实质性的脱离现状，重点是出租车司机在职业环境中的UFP暴露，并开发新的低成本技术，以减少他们的暴露。拟议的研究意义重大，因为它是一系列研究的第一步，这些研究确定了处于风险中的工人，保护工人免受高暴露，揭示了UFP在职业环境中的健康影响，并最终减少了UFP引起的疾病的工作场所负担。 公共卫生相关性：这项研究将提供一个强有力的科学依据，以制定具有成本效益的战略，保护出租车司机免受工作中排放的交通废气的影响，并将导致新的监管和监测方法，以控制相关的健康危害。这项研究与NIOSH的使命一致，即在职业安全和健康领域产生新的知识，并将这些知识转化为实践，以改善工人的生活。

DESCRIPTION (provided by applicant): In an urban environment, vehicular emissions usually constitute the largest source of ultrafine particles (UFPs, diameter <0.1 ¿m) and strong evidence from toxicological studies has demonstrated that UFPs are more toxic per unit mass than regulated larger particles. Taxi drivers are expected to be exposed to high levels of UFPs because of their close proximity to the source and prolonged exposure time. However, there is a critical data and knowledge gap on taxi drivers' exposure to UFPs at work and even less knowledge about the influencing factors leading to high exposures. Lack of such knowledge is an important problem because until reliable data and knowledge regarding exposure causes and correlates are available, quantitative UFP exposure/risk assessments cannot be completed and appropriate UFP mitigation policies cannot be set. Our long-term goal is to reduce occupational diseases attributable to exposure to UFPs at workplace. The objective of this proposal is to develop UFP exposure assessment instrument and explore novel low-cost UFP exposure mitigation strategies for taxi drivers. The central hypothesis is that 1) vehicle characteristics and driving conditions will explain a significant portion of the total variability f taxi drivers' exposure to UFPs; and 2) replacing commercially installed vehicle cabin filters with high efficiency particulate air (HEPA) filters will significantly re- duce taxi drivers' exposure t UFPs. Guided by preliminary data, this hypothesis will be tested by pursuing two specific aims: 1) develop exposure assessment instrument by identifying major factors that influence UFP concentrations inside taxi cabins; and 2) develop novel low-cost exposure mitigation strategies to reduce taxi drivers' exposure to UFPs. This will be the first systematic study to assess UFP exposures among taxi drivers in the US and the first study to explore cost-effective techniques to reduce UFP levels inside taxicabs. This study will benefit both taxi drivers, who normally spend 72 hours per week at work, and susceptible passengers, such as elderly and people with disabilities who require taxi service more frequently. We will monitor UFP and other vehicular emitted pollutant levels simultaneously inside and outside 40 taxis, build statistical models to predict in-cabin UFP levels, and test to what extent retrofitting commercially installed vehicle cabin air filters with HE- PA filters will reduce in-cabin UFP levels. The rationale for the proposed research is that the developed expo- sure model will facilitate subsequent health effect studies and the identified mitigation strategies will result in new and innovative approaches to prevent taxi drivers from high UFP exposures at work. The proposed re- search is innovative because it represents a new and substantive departure from the status quo by focusing on UFP exposure among taxi drivers in the occupational setting and developing novel low-cost technologies to re- duce their exposure. The proposed research is significant because it is the first step in a continuum of research that identifies workers at risk, protects workers fom high exposures, reveals the health effects of UFPs in the occupational setting, and ultimately reduces the workplace burden of diseases attributable to UFPs. PUBLIC HEALTH RELEVANCE: This study will provide a strong scientific basis for cost-effective strategies to protect taxi drivers from traffic emissions at work and will lead to new regulatory and monitoring approaches for controlling related health hazards. This research is aligned with NIOSH's mission to generate new knowledge in the field of occupational safety and health and to transfer that knowledge into practice for the betterment of workers.